This invention relates to air ionizing apparatus and more particularly to an elongated structure including a plurality of nozzles and ion emitter electrodes arranged along the length of the structure for delivering air ions toward a statically charged object.
Certain known devices for delivering air ions include elongated structures including multiple outlets spaced along the structure to promote release of air or other gas under pressure around an ion-emitting electrode in order to carry generated ion away from the outlet in a stream of flowing air. Such structures are commonly referred to as ionizer or corona discharge bars and are conventionally mounted overhead above regions where objects such as semiconductor wafers are positioned during fabrication processes. Such corona discharge bars commonly include an elongated channel that carries air or other gas under pressure, and that is arrayed at regular intervals with outlets or nozzles for the gas under pressure. Additionally, each such outlet includes a high-voltage electrode structure disposed in or around the outlet to receive ionizing high voltage for generating ions of one or other polarity in the outlet flow of the gas under pressure. Such conventional corona discharge bars commonly require selective shaping of the outlet for directing the outlet gas flow that compromises the ion-generating efficiency of the emitter electrodes. Similarly, selective shaping of the emitter electrodes for efficient ion generation commonly disrupts laminar air flow through the outlets. Also, such conventional corona discharge bars commonly incorporate high-voltage circuitry within the channel for delivering gas under pressure in order to conserve space and to facilitate convenient assembly and connection of the emitter electrodes with the internal high-voltage circuitry. Since the emitter electrodes erode and require periodic replacement, removal of the emitter electrodes from the outlets commonly exposes the delivery channel to ambient air and associated contaminants that tend to electrostatically adhere to the internal high voltage circuitry, with concomitant potential for undesirable random disbursement of contaminant particles from the outlets.
In accordance with one embodiment of the corona discharge bar of the present invention, component chambers of the bar for air flow and high-voltage circuitry are separated in an elongated structure that is easily assembled and that promotes close spacing of outlets along the length of the bar for efficient ion generation and delivery. An upper chamber includes high-voltage circuitry isolated from a lower chamber that forms a supply channel for gas under pressure, and the upper and lower chambers are latched together in assembled configuration by an exterior, non-ionizing electrode. Insulative support housings for the emitter electrodes include gas-flow outlets that promote laminar flow therethrough of air or other gas under pressure surrounding the emitter electrodes, and those support housings conveniently protrude from openings periodically spaced along the length of the air-flow chamber. The entire structure is aerodynamically configured to facilitate air flow downwardly over the structure without disturbing laminar air flow, for example, from overhead HEPA filtration of downdraft air flow.